Aluminum alloy.



m en wr ivr, or Sentacnrnnsnn, NEAR BERLIN, GERMANY.

ALUMINUM ALLOY.

No Drawing.

To all whom it may concern Be it known that I, ALFRED WILM, a subject of-the German Emperor, residing at Schlachtensee, near Berlin, Germany, have invented certain new and useful Improvements in Aluminum Alloys, of which the following is a specification.

My invention relates to improvements in aluminum alloys.

The advantages, of aluminum as regards weight and its many disadvantages as to lack of rigidity, difficulty of working and the like are well known.

Many alloys of aluminum have been made in the attempt to provide a metal which while retaining the advantages of aluminum will be free from its disadvantages. For example, it is old to form an alloy of aluminum, magnesium, and copper or manganese,

the heavy metal such as copper or manganese being added in the attempt to pr'oduce an alloy which can be worked in a manner more satisfactory than aluminum. It has also been proposed to improve the workability and hardness of an alloy of copper and alminum by the additionof chromium or manganese.

I have found that a valuable improvement in aluminum alloys will result by combining small quantities of manganese, with aluminum, magnesium and copper, the properties of the resultant alloy being very advantageous as compared with anything heretofore known, and at. the same time these properties are capable of modification according to the proportions of the manganese combined in the alloy. But the alloy is particularly advantageous when the percentage of magnesium is two-per cent. or below. An addition of manganese, for example, to an alloy of 93.1 to 96.5 per cent. aluminium, 0.5 per cent. magnesium, 5.6 to 3 percent. copper, causes,'even with an addition of only 0.5 per cent. an increase in strength of about 17 per cent, and an increase of hardness (by the ball test) of about 10 per cent, while at the same time the metal may be worked better, that is to say, it can be bored, drilled, planed, filed, ground or otherwise worked without the difficulties which are experiencedin performing such operations on commercial-aluminum or those aluminum alloys which resemble aluminum.

While I have mentioned 0.5 per cent. of manganese, as a striking example, it is to be understood that I do not limit my inven- Specification of Letters Patent.

Patented Mar. 9,,1915,

Application filed July 31, 191.1. Serial No. 641,625.

tion to this percentage, as even a smaller percentage of the added metal gives a considerable improvement in the alloy, while on the other hand a higher percentage of the added metal gives a still greater action though not necessarily "an improvement proportional to the increased quantity. The

necessary quantity of the manganese added to the aluminum-copper-magnesium alloy is determined by the quantity of copper and magnesium contained in the alloy.

- As an illustration of some of the great advantages obtained by my invention, I call attention to the following table of results obtained. Assuming that one starts with an alloy containing 3% copper and 0.5% magnesium, the following table shows theresults obtained by using instead of an 1ncreased amount of copper 1% instead of 3%) a small amount of manganese, for example, to 1%.

Strength Exten- Hardness Alloy. kg. per $1011 perb the square mm. centage. be test.

3%011. 0.5 Mgl'96.5 A1 as 25 9s 3% 0 10.5 Mg.+1% on. 95.5% A1. 38.5 22 109 3% Cu. 0.5 M .+0.5 Mn. 96% 111.. 41 22.5 108 3%Cu. 0.5 Mg.+1% Mn. 95.5%111. 43 go 113 The amount of metal which can be added to the alloy is limited to a certain extent by the contents of the copper ormagnesium in the alloy. per, manganese can be added from about 0.1% to at the highest about 1%. With.

not exceeding 6 per cent.

To analloy containing 5% copper, magnesium and manganese, the copper V 3. An alloy comprising aluminum, cop magnesium, about 3 per cent. of copper and 10 per, magnesium and manganese, the man-v about 1 per cent. of manganese.

galrese not exceeding 3 per cent. In Witness whereof I have hereunto affixed 4. An alloy comprising aluminum, copmy hand.

5 per magnesium and manganese the copper not exceeding 6 percent. and the manganese ALFRED not exceeding '8 per cent. Witnesses:

5. An alloy comprising about 95.5 per HENRY HABPER,

cent. of aluminum, about 0 .5 per cent. of WOLDEMAR UPT. 

